1. Field of the Invention
This invention relates to X-ray devices and more particularly to dental diagnostic X-ray devices.
2. Prior Art
Dental diagnostic X-ray installations wherein the unit includes a cathode emitter maintained in a housing and which is associated with means for focusing the electron beam from the cathode and directing it to an anode disposed in a sealed tube which projects from the housing are known to the art. Such constructions include devices wherein the tube which is attached to the X-ray tube, or to the cathode housing, is dimensioned to be inserted into the mouth of the patient. In such constructions the anode is normally constructed in a manner in which the X-radiation emitted issues in substantially all directions. Further, it has been known to provide a cap for the anode containing tube, the cap composed of a material which is absorptive of the radiation, the cap can be slipped over the sealed anode tube. The cap may then be provided with an aperture or opening restricting the resultant emitting beam from the cap to a chosen area. In this manner the device can allow the simultaneous photographing of several teeth while the anode is disposed in the mouth of the patient.
A diagnostic installation of the above described type is shown in U.S. Pat. No. 1,881,448. In this type of installation, the anode tube can be inserted into the mouth of the patient thus permitting so called dental status photographs, i.e. photographs of substantially all the teeth of a jaw. In such procedures the X-ray film is placed externally of the mouth of the patient and normally adjacent the face of the patient.
However, in addition to such dental status or survey type photographs, individual or limited area photographs continue to be required by modern dental practice for the examination of specific teeth. In most instances such specific examination photographs require the use of separate X-ray systems such as have been specifically designed for this purpose and are specific for the different types of photographic techniques used.
In addition, X-ray devices are also known which use two separate anodes and cathodes thereby providing versatility for both general or status type and individual or limited area photographs. Also known are devices utilizing X-ray tubes in which the electron beam can be selectively deflected or diverted to predetermine anode sections, thereby allowing both types of photographs to be taken. A primary disadvantage of these multi-use systems is that they are unwieldily in operation.